EP1180810A2 - Positives aktives Elektrodenmaterial für Lithium-ionenbatterie - Google Patents

Positives aktives Elektrodenmaterial für Lithium-ionenbatterie Download PDF

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Publication number
EP1180810A2
EP1180810A2 EP01119329A EP01119329A EP1180810A2 EP 1180810 A2 EP1180810 A2 EP 1180810A2 EP 01119329 A EP01119329 A EP 01119329A EP 01119329 A EP01119329 A EP 01119329A EP 1180810 A2 EP1180810 A2 EP 1180810A2
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Prior art keywords
positive electrode
electrode active
active material
lithium
represented
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French (fr)
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Tomaru Ogawa
Hidekazu Takahashi
Junji Katamura
Fumio Munakata
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Nissan Motor Co Ltd
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Nissan Motor Co Ltd
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Priority claimed from JP2000248961A external-priority patent/JP3578066B2/ja
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Publication of EP1180810A2 publication Critical patent/EP1180810A2/de
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/50—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese
    • H01M4/505—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present invention relates to a positive electrode active material using a lithium manganese compound of layered structure and to a rechargeable lithium-ion battery using the positive electrode active material.
  • the rechargeable lithium-ion battery can be used as a battery for a mobile unit, particularly for an electric vehicle such as an EV (Electric Vehicle) and an HEV (Hybrid Electric Vehicle).
  • a rechargeable lithium-ion battery has been expected as a secondary battery for an electric vehicle because it has a high charge/discharge voltage and a large charge/discharge capacity.
  • LiCoO 2 As a positive electrode active material for the rechargeable lithium-ion battery described above, LiCoO 2 has heretofore been used. However, cobalt has been expensive, and stability thereof has been problematic. Therefore, use of a lithium manganese compound (LiMn 2 O 4 ) of spinel structure as a positive electrode active material has been proposed (Japanese Laid-Open Patent Publications Hei 11 -171550 (published in 1999) and Hei 11-73962(published in 1999)).
  • the spinel type LiMn 2 O 4 is more stable, and better in cyclic resistance in comparison with the conventional LiCoO 2 .
  • the cyclic resistance thereof at high temperature is not sufficient, thus causing a problem that the positive electrode material is dissolved in an electrolyte leading to deterioration of the negative electrode in performance.
  • a technique for substituting a part of Mn for a transition metal element or a typical metal element has been attempted.
  • the LiMn 2 O 4 with Mn partially substituted for various elements for the purpose of improving the cyclic resistance at high temperature has been disclosed in Japanese Laid-Open Patent Publication Hei 11-71115(published in 1999).
  • distortion is sometimes brought into a crystal structure thereof, leading to deterioration of the cyclic resistance at room temperature.
  • substitution of a large quantity of elements is performed in order to stabilize the crystal structure for the purpose of improving the cyclic resistance, lowering of capacity of the positive electrode active material is brought.
  • the capacity of the spinel type LiMn 2 O 4 is 100 mAh/g, which is lower than the capacity of 140 mAh/g of the conventionally used LiCoO 2 based material.
  • the LiCoO 2 is unstable though it has a large capacity.
  • the spinel type LiMn 2 O 4 is not sufficient in cyclic resistance and the capacity thereof is small though it is stabler than the LiCoO 2 . Therefore, desired is development of a novel positive electrode active material provided with both of the large capacity and the high resistance.
  • the high-capacity layered LiMnO2 based material is employed as a positive electrode active material of the rechargeable lithium-ion battery, though a sufficient charge/discharge characteristic is obtained at, for example, 55°C, the capacity at room temperature is reduced to about one-third. Moreover, when charge and discharge are repeated at temperature higher than room temperature in order to secure the sufficient charge/discharge characteristic, the capacity is gradually reduced, and the sufficient cyclic resistance is not secured.
  • An object of the present invention is to provide a positive electrode active material of a layered lithium manganese compound which is excellent in the crystal structure stability.
  • Another object of the present invention is to provide a manufacturing method of the positive electrode active material of the layered lithium manganese compound.
  • Still another object of the present invention is to provide a rechargeable lithium-ion battery which employs the above positive electrode active material.
  • a first aspect of the present invention provides a lithium manganese compound of a layered crystal structure which is represented by a general formula Li 1-x MO 2 as a positive electrode active material for a rechargeable lithium-ion battery.
  • M is manganese or two or more kinds of metals containing manganese as a main component
  • x is a lithium-deficient quantity, and satisfies the following expression: 1/5 ⁇ x
  • a deficient structure is provided in a lithium site of the layered lithium manganese compound.
  • the deficient quantity x is larger than 1/5, a value of bond overlap population (BOP) as an index of the crystal structure stability, which is obtained by calculation using a molecular orbital method, can be increased. Therefore, when the layered lithium manganese compound is employed as a positive electrode active material, cyclic stability can be improved.
  • a second aspect of the present invention provides a manufacturing method of the positive electrode active material.
  • a lithium compound and a manganese compound are mixed in a ratio equivalent to the composition ratio of Li and Mn in the general formula Li 1-x MO 2 (x > 1/5). Then, a mixture obtained is baked in a low oxygen concentration atmosphere with an oxygen concentration of 1000 ppm or less.
  • a lithium-deficient type layered lithium manganese compound having high capacity and stability can be obtained.
  • a third aspect of the present invention provides a rechargeable lithium-ion battery which includes a positive electrode containing the above positive electrode active material; a negative electrode; and an electrolyte interposed between the both electrodes.
  • a rechargeable lithium-ion battery having a good cyclic stability and a high battery capacity can be provided.
  • the positive electrode active materials according to first and second embodiments of the present invention are layered lithium manganese compounds represented by the general formula Li 1-x MnO 2 .
  • the crystal of each compound can further be represented as Li 1-x Mn 1- y M y O 2 or Li 1-x Mn 1-y M y O 2- ⁇ .
  • the layered lithium manganese compound of a Li-deficient type with x larger than 0 is a novel material discovered by the inventors of the present invention, which has been introduced from a designing concept to be described below.
  • oxide such as NiO has a crystal structure in which Ni layers and oxidized layers are alternately arrayed in a ⁇ 111> orientation of the crystal.
  • the conventional layered LiMO 2 compound (where M is Ni, Co or Mn)
  • the layered lithium manganese compound taken as an example has a crystal structure to be described below.
  • oxygen planes and metal planes are alternately and repeatedly arrayed in such a manner as: oxygen layer - Mn layer - oxygen layer - Li layer - oxygen layer - Mn layer - oxygen layer, and further, planes (layers) having metal elements thereon are arrayed regularly and alternately.
  • the NaCl type MO crystal and the layered LiMO 2 compound are conceived to have structures very similar to each other.
  • the inventors of the present invention found out that the layered LiMO 2 compound is composed by repeatedly arraying MO crystal blocks.
  • the inventors found out that the layered LiMO 2 compound is composed by repeatedly arraying [LiO] [MO] blocks, in which MO blocks [MO] and LiO blocks [LiO] are arrayed alternately and repeatedly.
  • the crystal structure when the notation concerning the block structure described above is applied to a crystal structure of the conventionally known sodium manganese oxide Na 2/3 MnO 2 , the crystal structure can be represented as [Na 2/3 O] [MnO].
  • the crystal structure above is conceived to be a structure obtained by regularly reducing a Na occupation ratio in the [NaO] blocks of the [NaO] [MnO] blocks. This implies that novel layered sodium manganese oxide can be created by varying the Na-deficient quantity.
  • a layered LiMnO 2 compound taken as an example of the layered LiMO 2 compound there is a small difference between Li sites and Mn sites, where the "sites" indicate positions occupied by elements in the crystal structure. Therefore, by regularly reducing Mn occupation ratio also in the [MnO] blocks similarly to the [LiO] blocks, it is conceived that the novel layered LiMnO 2 compound can be obtained.
  • the inventors of the present invention found a layered lithium manganese compound of Li-deficient type obtained by making Li and Mn regularly deficient from a congruent composition of the layered lithium manganese compound and by substituting Li and Mn by a specified metal according to needs. Moreover, the inventors verified that the above-described material has a stable structure in comparison with the conventional layered lithium manganese compound and is suitable for the positive electrode active material.
  • composition of the layered lithium manganese compound of the Li-deficient type obtained through the above-described designing concept is provided.
  • the "BOP" value is obtained by calculation using a molecular orbital method, the structure stability is evaluated, and the Li-deficient quantity x is obtained.
  • substitution of Mn for the other metal is carried out, and what a preferable range of oxygen-deficient quantity ⁇ is by the calculation.
  • the molecular orbital method is widely known as a method for calculating an electronic state of a material, and is also used for evaluation of the positive electrode active material of a lithium ion battery (Jpn. J. Appl. Phys. vol. 38 p.2024 (1999)).
  • FIG. 2 illustrates procedures of the calculation using the molecular orbital method.
  • a basis function atomic orbital
  • P1 a kind of an atom
  • P2 an orbital energy, charge distribution and the like
  • P3 a molecular orbital (coefficient in linear bonding of atomic orbitals) is set from the obtained orbital energy and the like (P3).
  • the obtained molecular orbital, orbital energy, charge distribution and the like are compared with those previously obtained (P4). If differences therebetween are sufficiently small, that is, if 'Yes' in the flowchart, the molecular orbital is decided. Note that the determination whether or not the differences are sufficiently small is made depending on whether or not the number of effective electrons in each atom is changed before and after the calculation.
  • the cluster method is a method, in which a small group of atoms as a part of the crystal structures, taken out of molecules, or a cluster, is specified, and the molecular orbital calculation is performed for the cluster.
  • FIG. 3 shows a structure of the cluster.
  • the structure contains up to the fourth proximate atoms with the Mn atoms taken as centers when the layered lithium manganese compound is adapted to the NaCl type crystal structure.
  • a cluster model of the Li-deficient structure obtained by removing a part of Li from a Li layer (shown by dotted lines) in the cluster is employed.
  • FIG. 4 shows models of the Li-deficient structures. Each of triangles of FIG. 4 corresponds to the Li layer in FIG. 3.
  • the bond overlap population (hereinafter, referred to as "BOP") in between the central Mn atom and the first proximate oxygen atom of the cluster is obtained.
  • the BOP obtained by the "charge distribution" shown in FIG. 2 can evaluate the covalent of the oxygen layer and a metallic base layer represented by the Mn atoms, that is, the bonding stability, in the layered lithium manganese compound of the Li-deficient type. If a BOP value is high, it can be determined that the change in the crystal structure due to a thermal history is small, that is, the stability of the layered lithium manganese compound of the Li-deficient type is high. Therefore, a mean value of the BOPs of the central Mn atom and the proximate oxygen atoms (three in number) in each cluster can be assigned as an index of the cyclic stability of the cluster.
  • Specific calculation techniques of the above-described molecular orbital method include an ab initio molecular orbital method and a density functional theory (DFT) method. Selection of the calculation techniques may be decided depending on the scale of the cluster model. Since the density functional theory method carries out a coarse approximate calculation when compared to the ab initio molecular orbital method, it is suitable for calculation of a larger scale cluster with the same performance of hardware. Therefore, in the first embodiment, it is desirable that the density functional theory method is employed since a relatively large cluster model as shown in FIG. 3 is used. Specifically, a DV-X ⁇ method as one of the density functional theory methods is used. For the DV-X ⁇ method, the contents in J. Solid State. Chem. vol. 119, pp. 76-79 (1995) are incorporated by reference.
  • a positive electrode active material of a layered lithium manganese compound having high-capacity and stability which is suitable for the rechargeable lithium-ion battery, as described below, can be provided.
  • the positive electrode active material of the first embodiment is a layered lithium manganese compound of the Li-deficient type having a layered crystal structure, in which lithium is partially deficient from a congruent composition.
  • the positive electrode active material is represented by the following general formula (A): Li 1-x MO 2 where x is a Li-deficient quantity, and preferably satisfies the following expression: 1/5 ⁇ x more preferably, x satisfies the following expression: 1/5 ⁇ x ⁇ 1/2
  • the Li-deficient quantity x when the Li-deficient quantity x is larger than 1/2, the Li-containing quantity in the molecular crystal becomes smaller than that of the spinel type LiMn 2 O 4 . Since the capacity of the positive electrode active material depends on the Li-containing quantity, when x is larger than 1/2, it will be difficult to utilize the advantage of the layered structure in that the capacity is large. Therefore, when x is larger than 1/5 and smaller than 1/2, high capacity and cyclic stability of the crystal structure can be ensured.
  • M is a metal, and may be Mn or two or more kinds of metals containing Mn as a main component.
  • the formula (A) can be represented as the following formula (B) Li 1-x Mn 1-y M' y O 2 where M' denotes a substitution metal or substitution metals for which Mn is partially substituted and y denotes a substitution quantity thereof.
  • the substitution metal M' a 3d-transition metal is preferable because of its similarity in the atomic structure to Mn.
  • a typical metal and other transition metals can also be employed.
  • the 3d-transition metal includes, for example, iron (Fe), nickel (Ni), chromium (Cr), cobalt (Co), manganese (Mn) and the like.
  • substitution metal M' one kind of metal selected from the above or a combination of two or more kinds thereof can be employed. In any case, a high BOP value can be obtained.
  • c and d should be natural numbers ranging from 1 to 30 and also satisfy c ⁇ d.
  • the Li-deficient type layered lithium manganese compound of the first embodiment should have a crystal structure in which the Li-deficient quantity x and Mn-substitution quantity y are regularly controlled.
  • the crystal structure of the Li-deficient type layered lithium manganese compound can be stabilized.
  • the above-described lithium manganese compound is employed as the positive electrode active material of the rechargeable lithium-ion battery, the cyclic resistance of the battery can be improved.
  • the Li-deficient quantity x can be adjusted specifically into values such as 1/4, 3/10, 1/3, 3/8, 2/5 and 4/9.
  • the Mn-substitution quantity y can be adjusted specifically into values such as 1/4, 3/10, 1/3, 3/8, 2/5 and 4/9.
  • a composition variation range of the Li-deficient quantity x is preferably set at ⁇ 5%.
  • the Li-deficient quantity may be made locally uneven and desired performance may not be obtained.
  • a composition variation rage of the M-substitution quantity y is preferably set at ⁇ 5%.
  • the metal composition ratio may be made locally uneven and desired performance may not be obtained.
  • oxygen (O) in the formula (B) may be made partially deficient from the congruent composition.
  • the layered lithium manganese compound of the Li-deficient type in this case can be represented by the following formula (C). Li 1-x Mn 1-y M' y O 2- ⁇ where ⁇ denotes an oxygen-deficient quantity, and preferably satisfies the following expression: ⁇ ⁇ 0.2
  • the oxygen-deficient quantity ⁇ is equal to or less than 0.2, a high BOP value can be obtained. Accordingly, good structure stability can be obtained. while when ⁇ is greater than 0.2, the oxygen-deficient quantity is too large, and thus the crystal structure tends to be unstable.
  • the substitution metal M' can be substituted for one of the typical metal element or the transition metal element excluding Mn, Cr and Co, or for a metal M" in accordance with any combination of the above-described metal elements.
  • the formula (C) can also be represented by the following formula (D). Li 1-x Mn 1-y M' y(1-Z) M'' yz O 2- ⁇ where z is a M'-substitution quantity, and is preferably a rational number.
  • z is represented as e/f, desirably, e and f are natural numbers ranging from 1 to 30 and also satisfy e ⁇ f.
  • the BOP values of each example where the Li-deficient quantities x range from 0 (no deficiency) to 1/2 were evaluated by use of the density functional theory method. Additionally, each of the theoretical capacities of the examples was also obtained. In the examples 1 to 4, the Li-deficient quantities x are 1/4, 3/10, 1/3 and 2/5, respectively. In the comparative examples 1 to 4, the Li-deficient quantities x are 1/2, 0, 1/6 and 1/5, respectively.
  • FIG. 5 is a table listing the evaluation results. In addition, the relative BOP values in the case where the BOP value of the comparative example 2 is set as 1 are also listed.
  • Li 0.75 MnO 2- ⁇ the BOP value and the theoretical capacity were evaluated.
  • Li 0.67 MnO 2- ⁇ the BOP value and the theoretical capacity were evaluated.
  • Li 0.6 MnO 2- ⁇ the BOP value and the theoretical capacity were evaluated.
  • Li 0.8 MnO 2- ⁇ the BOP value and the theoretical capacity were evaluated.
  • FIG. 6 is a table listing the obtained results.
  • Li 0.75 Mn 0.67 Fe 0.33 O 2- ⁇ the BOP value and the theoretical capacity were evaluated.
  • Li 0.75 Mn 0.67 Ni 0.33 O 2- ⁇ the BOP value and the theoretical capacity were evaluated.
  • Li 0.75 Mn 0.75 Fe 0.25 O 2- ⁇ the BOP value and the theoretical capacity were evaluated.
  • Li 0.75 Mn 0.75 Ni 0.25 O 2- ⁇ the BOP value and the theoretical capacity were evaluated.
  • Li 0.67 Mn 0.67 Fe 0.33 O 2- ⁇ the BOP value and the theoretical capacity were evaluated.
  • Li 0.67 Mn 0.67 Ni 0.33 O 2- ⁇ the BOP value and the theoretical capacity were evaluated.
  • the BOP values of the examples 11 to 15 where the Li-deficient quantities x are 1/4, the Mn-deficient quantities y are 1/3, 2/3 and 1/2, and the substitution metal is Cr, Co and Al were obtained.
  • the BOP values of each of the comparative examples 5 and 6 where the Li-deficient quantities x are 1/5 and 1/3, the Mn-deficient quantities y are 1/3 and 2/3, and the substitution metal is Cr and Co were obtained.
  • FIG. 7 is a table listing the obtained results.
  • Li 0.75 Mn 0.67 Cr 0.33 O 2- ⁇ the BOP value and the theoretical capacity were evaluated.
  • Li 0.75 Mn 0.67 Co 0.33 O 2- ⁇ the BOP value and the theoretical capacity were evaluated.
  • Li 0.75 Mn 0.33 (Cr 0.5 Co 0.5 ) 0.67 O 2- ⁇ the BOP value and the theoretical capacity were evaluated.
  • Li 0.75 Mn 0.5 (Cr 0.8 Al 0.2 ) 0.5 O 2- ⁇ the BOP value and the theoretical capacity were evaluated.
  • Li 0.75 Mn 0.5 (Cr 0.4 Co 0.4 Al 0.2 ) 0.5 O 2- ⁇ the BOP value and the theoretical capacity were evaluated.
  • Li 0.8 Mn 0.67 Cr 0.33 O 2- ⁇ the BOP value and the theoretical capacity were evaluated.
  • Li 0.67 Mn 0.37 Co 0.33 O 2- ⁇ the BOP value and the theoretical capacity were evaluated.
  • the BOP values are as large as 0.23 or more, verifying that the cyclic properties are significantly improved.
  • the BOP values are as large as 0.23 or more, verifying that the cyclic stability is high.
  • the BOP value when Mn is partially substituted for Fe or Ni is larger that when the metallic base is only Mn, verifying that the cyclic stability is improved.
  • each of the rechargeable lithium batteries of the examples above can be expected for use as a compact, long-life battery for an EV or a HEV.
  • the positive electrode active material of the second embodiment is also represented by the general formula Li 1-x MO 2
  • the main metal composition is not necessarily limited to manganese.
  • the positive electrode active material includes the one without lithium deficiency. Accordingly, the positive electrode active material here is referred to simply as a layered lithium compound.
  • the molecular orbital calculation using the cluster method is carried out similarly to the first embodiment.
  • a metallic base and oxygen atoms at the periphery thereof in the layered lithium compound are used as a cluster model.
  • FIG. 8 shows a cluster structure of three metal atoms. Such a cluster reproduces metal atoms of the layered lithium compound and two oxygen layers sandwiching a metal layer represented by the metal atoms.
  • the cluster is a model reasonable for investigating the effect of the metallic base of the layered lithium compound.
  • the BOP value between the Mn atom in the cluster shown in FIG. 8 and the oxygen atom sandwiched between the Mn atom and the other metal atom is obtained.
  • the covalent between the metallic base layer represented by the Mn atom and the oxygen layer, that is, the bonding stability is evaluated.
  • a mean value of the BOPs of the Mn atom in the cluster and the oxygen atoms, where two oxygen atoms per one Mn atom exist, sandwiched between the Mn atom and the metal atoms adjacent thereto is an index of the stability of the cluster and the crystal structure from which the cluster is taken out.
  • the ab initio molecular orbital method should be used as a specific calculation technique of the molecular orbital method.
  • the contents of Physical Review B, vol. 53, No. 7, pp. 3731-3740(1996)) and Physical Review B,vol. 57, No. 24, pp. 15211-15218(1998)) are incorporated by reference.
  • the high-capacity and stable positive electrode active material suitable for the rechargeable lithium-ion battery is obtained as described below.
  • the layered lithium compound according to the second embodiment is represented by the following general formula (A): Li 1-x MO 2 where M is two kinds of metal elements with a difference of the number of electrons being an odd number, in which one or both of the metal elements is a 3d-transition metal.
  • the metal element M should be two kinds of metal elements, and the difference of the number of atoms should be an odd number. If the difference of the number of electrons is an even number, the BOP value is lower than the case where the difference of the number of electrons is an odd number. Thus, the stability of the crystal structure is lowered.
  • one or both of the two kinds of metal elements should be a 3d-transition metal. If both of the metal elements are not 3d-transition metals, the stability of the crystal structure and the resistance of the compound at room temperature are lowered.
  • the 3d-transition metal may include, for example, manganese (Mn), chromium (Cr), iron (Fe), nickel (Ni), cobalt (Co) and vanadium (V) and the like.
  • the general formula (A) is represented by the following formula (B): Li 1-x Mn 1-y M' y O 2 where M' is a metal for which manganese is substituted, and y denotes a substitution quantity thereof.
  • substitution metal M' chromium, iron and nickel are preferable. With these metals, Mn can readily construct a stable crystal structure.
  • the effect of the metal composition is also exerted even when the lithium-deficient quantity x is 0, that is, even when the lithium deficiency is not present.
  • the lithium-deficient quantity x is preferably at least 0.03 or larger.
  • each of a and b should be an arbitrary natural number selected from 1 to 30, and should satisfy: a ⁇ b.
  • the lithium-deficient quantity x can be: 1/2, 1/3, 2/3, 1/4, 1/5, 2/5, 1/6 or 1/8.
  • the lithium-deficient quantity is set as 1/5 or larger, more preferably set in the following range: 1/5 ⁇ x ⁇ 1/2
  • the composition variation range is preferably set within ⁇ 5%.
  • the composition variation range exceeds ⁇ 5%, the crystal structure becomes partially inconsistent with an intended composition, resulting in distortion in some cases.
  • the Mn substitution quantity y can be represented by a ratio of c/d.
  • c and d is preferably an arbitrary natural number selected from 1 to 30, and satisfies: c ⁇ d.
  • the Mn substitution quantity y can be adjusted as: 1/2, 1/3, 2/3, 1/4, 1/5, 2/5, 1/6 or 1/8.
  • oxygen (O) in the formula (B) may be made partially deficient from the congruent composition.
  • the layered lithium manganese compound of the Li-deficient type in this case can be represented by the following formula (C): Li 1-x Mn 1-y M' y O 2- ⁇ where ⁇ denotes an oxygen-deficient quantity.
  • ⁇ denotes an oxygen-deficient quantity.
  • the value of ⁇ is preferably set at 0.2 or less. When ⁇ is larger than 0.2, the oxygen-deficient quantity is too much to prepare it. Moreover, the one produced tends to have an unstable crystal structure.
  • LiMnO 2 can be written as [LiO] [MnO] by use of block structure description.
  • the layered lithium manganese compound of the Li-deficient type of the second embodiment is composed by controlling the Li-deficient quantity and the element substitution quantity of the Mn sites. Therefore, by use of block structure description, the layered lithium manganese compound represented by the formula (B) can be written as [Li 1-x O] [Mn 1-y M' y O].
  • the layered lithium manganese compound can be written as [Li 2/3 O] [Mn 1/2 M' 1/2 O].
  • the substitution metal M' is Ni
  • a Li-deficient metal compound represented by the formula Li 2/3 Mn 1/2 Ni 1/2 O 2 is obtained.
  • the crystal structure can be stabilized, and the cyclic resistance of the compound when used as the positive electrode active material of the rechargeable lithium-ion battery can be improved.
  • the Mn substitution quantity y to a specified ratio of c/d, making the Mn regularly deficient, and substituting the specified substitution metal M', the resistance and the stability of the compound at high temperature can be obtained.
  • the cluster models shown in FIGs. 8 and 9 were used to perform calculation using the ab initio molecular orbital method, and the BOP values of the layered lithium manganese compounds (Li 1-x Mn 1-y M' y O 2- ⁇ ) in the examples and the comparative examples were obtained.
  • the BOP value of the cluster without metal substitution was set as 1.00, and relative comparison thereof was made with the BOP value of the cluster with the same number of metal atoms.
  • substitution metal M' partially substituting Mn examination was carried out for Cr, Fe, Ni and Co.
  • the substitution quantity y was set as: 0, 1/2 and 1/3.
  • FIG. 10 is a table listing the results.
  • the cluster model of two metal atoms was used.
  • metal atoms Mn and Cr were selected.
  • the cluster model of two metal atoms was used.
  • metal atoms Mn and Fe were selected.
  • the cluster model of two metal atoms was used. As metal atoms, Mn and Ni were selected.
  • the cluster model of three metal atoms was used.
  • metal atoms Mn (two atoms) and Cr were selected.
  • the cluster model of three metal atoms was used.
  • metal atoms Mn (two atoms) and Fe were selected.
  • the cluster model of three metal atoms was used.
  • metal atoms Mn (two atoms) and Ni were selected.
  • the cluster model of two metal atoms was used.
  • metal atoms Mn (two atoms) was selected.
  • the cluster model of two metal atoms was used.
  • metal atoms Mn and Co were selected.
  • the cluster model of three metal atoms was used.
  • metal atoms Mn (three atoms) was selected.
  • the cluster model of three metal atoms was used.
  • metal atoms Mn (two atoms) and Co were selected.
  • the BOP value when Cr, Fe or Ni in which the difference of the number of atoms with Mn is an odd number is selected as the substitution metal is apparently higher than the BOP value when Co in which the difference of the number of atoms with Mn is an even number and the BOP value when no substitution metal is present (the difference of the number of atoms is 0).
  • the stability of the crystal structure is high when Mn is made regularly deficient and substituted for a specified metal element as in the embodiment.
  • each of the rechargeable lithium batteries of the examples can be expected for use as a compact, long-life battery for an EV or a HEV.
  • Mn has been set as one of the metals in the above-described examples and comparative examples, it can be assume that the metal can be the one in which two kinds of 3d-transition metal are contained.
  • the positive electrode active material according to the first embodiment the layered lithium manganese compound of the Li-deficient type
  • the positive electrode active material according to the second embodiment the layered lithium compound
  • each of the positive electrode active materials specified quantities of the lithium compound and the manganese compound or other metal compounds are mixed so as to obtain a molar ratio of lithium and manganese or other metals in response to the formula of the crystal composition to be prepared, and then the mixture is baked.
  • lithium compound lithium carbonate, lithium hydroxide, lithium nitrate, lithium acetate or the like can be used.
  • lithium carbonate or lithium hydroxide are preferable to be employed.
  • the average particle diameter of the lithium compounds described above is desirably 30 ⁇ m or less.
  • manganese compound for example, manganese dioxide prepared by electrolysis, manganese dioxide prepared by chemical synthesis, dimanganese trioxide, ⁇ -MnOOH, manganese carbonate, manganese nitrate, manganese acetate or the like can be employed.
  • each manganese compound should be employed in the form of powder.
  • the average particle diameter of the manganese compound is preferably set in a range from 0.1 to 100 ⁇ m, more preferably, at 20 ⁇ m or less. When the average particle diameter of the manganese compound powder is large, reaction of the manganese compound and the lithium compound becomes significantly slow, and uniformity of the products tends to be worse.
  • the lithium compound and the manganese compound should be mixed with a uniform molar ratio overall.
  • a carbon-containing compound desirably, carbon powder such as carbon black and acetylene black
  • an organic matter such as citric acid
  • a quantity of such additive is preferably set in a range from 0.05 to 10%, more preferably, in a range from 0.1 to 2%. When the quantity of additive is small, an effect thereof tends to be lowered. When the quantity of additive is large, a sub-product tends to be created and the purity of the target product may be worse due to the remains of the added carbon-containing compound.
  • the baking of the mixture must be carried out in an atmosphere with a low oxygen concentration.
  • the baking is desirably carried out in an atmosphere of nitrogen, argon, or carbon dioxide, that is, in a gas atmosphere not containing oxygen.
  • the partial pressure of oxygen is preferably 1000 ppm or lower, more preferably, 100 ppm or lower. When the partial pressure of oxygen is more than the above-described value, the baking cannot be carried out in some cases.
  • the baking temperature is preferably fixed at 1100°C or lower, more preferably, 950°C or lower. When the baking temperature exceeds 1100°C, the product tends to be decomposed.
  • the baking time is preferably set in a range from 1 to 48 hours, more preferably, in a range from 5 to 24 hours. Still further, the baking method is not limited to one-step baking, but a multistep baking with a varying baking temperature may be performed according to needs.
  • FIG. 11 shows a representative structure example of the rechargeable lithium-ion battery.
  • a wound device in a roll fashion which includes a positive electrode 10 with a positive electrode active material coated on both surfaces of a metal foil collector, a negative electrode 20 with a negative electrode material coated on both surfaces of a metal foil collector similarly, and a separator 30 interposed between the both electrodes, is accommodated in a cylindrical sealing case 40.
  • An electrolyte electrolytic solution
  • an anode terminal 50 is provided on the upper portion of the case 40, and on the lower portion thereof, an anode terminal 50 is provided.
  • the layered lithium manganese compound of the Li-deficient type according to the first embodiment or the layered lithium compound according to the second embodiment can be employed.
  • an electrode material for use in a typical non-aqueous electrolytic secondary battery is usable.
  • the usable electrode material includes Li metal, complex oxide, nitride, carbon material, and any combination of the above.
  • metal lithium, lithium alloys, metal oxide such as SnSiO 3 , metal nitride such as LiCoN 2 , a carbon material such as graphite and hard carbon, and any combination of the above can be exemplified.
  • the carbon material coke, natural graphite, artificial graphite or non-graphitizable carbon can be employed.
  • the electrolyte the one obtained by dissolving a lithium salt as an electrolyte into non-aqueous solvent such as organic solvent can be used.
  • a lithium salt specifically, LiClO 4 , LiAsF 6 , LiPF 6 , LiBF 4 , LiCF 3 SO 3 and Li(CF 3 CO 2 ) 2 N, which have been publicly known, can be exemplified.
  • the organic solvent is not particularly limited, but a carbonate group, a lactone group and an ether group can be employed.
  • the solvent such as ethylene carbonate, propylene carbonate, diethyl carbonate, dimethyl carbonate, methyl ethyl carbonate, 1,2-dimethoxyethane, 1,2-diethoxyethane, tetrahydrofuran, 1,3-dioxolane and ⁇ -butyrolactone can be employed singly or mixedly with two kinds or more.
  • the concentration of the electrolyte dissolved in the solvent described above is desirably set in a range of 0.5 to 2.0 mol/L.
  • an ion-conductive high-molecular solid electrolyte can be employed.
  • a solid or viscous liquid dispersed evenly in a high-molecular matrix or the one obtained by immersing a non-aqueous solvent into such a solid or viscous liquid can be can be used.
  • the high-molecular matrix polyethylene oxide, polypropylene oxide, polyacrylonitrile, polyvinyliden fluoride and the like can be exemplified.
  • the separator can prevent a short circuit between the positive electrode and the negative electrode.
  • a porous sheet, a fine porous film, a non-woven fabric or the like, composed of materials such as polyethylene, polypropylene and cellulose, can be employed.
  • the rechargeable lithium-ion battery of the embodiment is excellent in the cyclic resistance, it is suitable as a battery mounted on the mobile unit such as an electric vehicle.
  • FIGs. 12A and 12B show examples of the electric vehicles mounting the rechargeable lithium batteries of the embodiment.
  • the mounting positions of the batteries are not limited, but as shown in FIGs. 12A and 12B for example, each of the batteries is provided on the bottom of the vehicle body, and each of the charge terminals is provided in the front or rear of the vehicle body so as to facilitate a manual charging operation.
  • the electric energy discharged from the charged battery drive the motor provided in the front or rear of the vehicle body.
EP01119329A 2000-08-18 2001-08-10 Positives aktives Elektrodenmaterial für Lithium-ionenbatterie Withdrawn EP1180810A2 (de)

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JP2000248962A JP2002060223A (ja) 2000-08-18 2000-08-18 Ｌｉ含有金属複合酸化物及びこれを用いた非水電解質二次電池
JP2000248962 2000-08-18
JP2000248961 2000-08-18
JP2000248961A JP3578066B2 (ja) 2000-08-18 2000-08-18 Ｌｉ欠損マンガン複合酸化物及びこれを用いた非水電解質二次電池

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WO2003009407A2 (en) * 2001-07-14 2003-01-30 The University Court Of The University Of St Andrews Managanese oxide material for electrochemical cells
WO2003044881A1 (fr) * 2001-11-22 2003-05-30 Yuasa Corporation Materiau actif d'electrode positive pour cellule secondaire au lithium et cellule secondaire associee
US8679670B2 (en) 2007-06-22 2014-03-25 Boston-Power, Inc. CID retention device for Li-ion cell
EP2734474A2 (de) * 2011-07-20 2014-05-28 Hanwha Chemical Corporation Einphasiges und mehrkomponentiges übergangsmetalloxid mit geringem lithiumanteil und einer geschichteten kristallstruktur sowie verfahren zu seiner herstellung

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US7771874B2 (en) * 2005-06-29 2010-08-10 Fmc Corporation Lithium manganese compounds and methods of making the same
JP5962429B2 (ja) * 2012-10-22 2016-08-03 ソニー株式会社 電池、電池パック、電子機器、電動車両、蓄電装置および電力システム
KR101513496B1 (ko) 2013-07-24 2015-04-20 주식회사 엘지화학 리튬 망간계 산화물 및 이를 포함하는 양극 활물질
JP6156078B2 (ja) 2013-11-12 2017-07-05 日亜化学工業株式会社 非水電解液二次電池用正極活物質の製造方法、非水電解液二次電池用正極及び非水電解液二次電池
JP6524651B2 (ja) 2013-12-13 2019-06-05 日亜化学工業株式会社 非水電解液二次電池用正極活物質及びその製造方法
WO2017013848A1 (ja) 2015-07-23 2017-01-26 パナソニックＩｐマネジメント株式会社 正極活物質、および、電池
WO2017047019A1 (ja) 2015-09-16 2017-03-23 パナソニックＩｐマネジメント株式会社 電池
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EP3352262B1 (de) 2015-09-16 2019-10-16 Panasonic Intellectual Property Management Co., Ltd. Positivelektrodenaktivmaterial und batterie
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CN107408687B (zh) 2015-09-16 2022-01-28 松下知识产权经营株式会社 正极活性物质和电池
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US10483541B2 (en) 2016-05-09 2019-11-19 Nichia Corporation Method of producing nickel-cobalt composite hydroxide and method of producing positive electrode active material for non-aqueous electrolyte secondary battery
JP6979586B2 (ja) 2016-11-15 2021-12-15 パナソニックＩｐマネジメント株式会社 電池用正極活物質、および、電池用正極活物質を用いた電池
WO2018092359A1 (ja) 2016-11-15 2018-05-24 パナソニックＩｐマネジメント株式会社 電池用正極活物質、および、電池
JP6964246B2 (ja) 2016-12-02 2021-11-10 パナソニックＩｐマネジメント株式会社 正極活物質、および、正極活物質を用いた電池
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US11233241B2 (en) 2017-11-13 2022-01-25 The University Of New Hampshire Preparation of: I. intercalative metal oxide/conductive polymer composites as electrode materials for rechargeable batteries; II. sodium rich manganese oxide hydrate with capacity for aqueous Na-ion electrochemical energy storage
WO2019094907A2 (en) * 2017-11-13 2019-05-16 The University Of New Hampshire PREPARATION OF: I. INTERCALATIVE METAL OXIDE/CONDUCTIVE POLYMER COMPOSITES AS ELECTRODE MATERIALS FOR RECHARGEABLE BATTERS; II. SODIUM RICH MANGANESE OXIDE HYDRATE WITH CAPACITY FOR AQUEOUS Na-ion ELECTROCHEMICAL ENERGY STORAGE

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WO2003009407A2 (en) * 2001-07-14 2003-01-30 The University Court Of The University Of St Andrews Managanese oxide material for electrochemical cells
WO2003009407A3 (en) * 2001-07-14 2004-10-28 Univ St Andrews Managanese oxide material for electrochemical cells
WO2003044881A1 (fr) * 2001-11-22 2003-05-30 Yuasa Corporation Materiau actif d'electrode positive pour cellule secondaire au lithium et cellule secondaire associee
US7393476B2 (en) 2001-11-22 2008-07-01 Gs Yuasa Corporation Positive electrode active material for lithium secondary cell and lithium secondary cell
US8679670B2 (en) 2007-06-22 2014-03-25 Boston-Power, Inc. CID retention device for Li-ion cell
EP2734474A2 (de) * 2011-07-20 2014-05-28 Hanwha Chemical Corporation Einphasiges und mehrkomponentiges übergangsmetalloxid mit geringem lithiumanteil und einer geschichteten kristallstruktur sowie verfahren zu seiner herstellung
EP2734474A4 (de) * 2011-07-20 2015-04-01 Hanwha Chemical Corp Einphasiges und mehrkomponentiges übergangsmetalloxid mit geringem lithiumanteil und einer geschichteten kristallstruktur sowie verfahren zu seiner herstellung

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